1. Field of the Invention
This invention relates to surgical instruments having a working head with an associated movable element that is controllable from a location remote from the working head.
2. Background Art
Delicate surgical operations such as microsurgery and laparoscopy surgery often require precise control over jaws or blades of instruments used in the procedure. In order to achieve maximum control over these instruments, it is necessary to use the intrinsic muscles of the hand which are capable of considerable control and remarkable finesse. It is known that muscles that control motion of the fingers are capable physiologically of more precise motion than muscles that control flexion, extension or rotation of the wrist or those muscles that control supination/pronation of the forearm. The motor and sensory innervations of the hand are significantly out of proportion to the size or bulk of the hand.
Heretofore, surgical instruments have not been designed to exploit the hand muscles that give maximum dexterity. For example, one type of instrument has a scissors-type grip which is operated to slide a cable or actuating link within a flexible casing to selectively open and close cooperating jaws, blades or the like. To effect rotation of the jaws the entire instrument must be rotated through the grip primarily with the wrist which, as previously described, gives the user a limited amount of control.
If the casing is not maintained perfectly straight, part of the instrument will not rotate about the axis of the casing. Substantial tissue damage may then occur. Additionally, the working head might nutate upon rotation of the instrument. This cannot be tolerated in delicate surgical procedures.
Another problem with the aforementioned structure is that the user must constantly maintain pressure on the grip to close the jaws or the blades. It is awkward and inconvenient to squeeze the grip as the instrument is being used during an operation and muscular fatigue is inevitable.
Another problem in gynecological microsurgery that has been inadequately dealt with by the prior art is that of tying delicate sutures in areas which are not readily accessible. Procedures now used generally inordinately lengthen operative time. There is also a tendency of sutures formed by conventional techniques to loosen and release altogether.